This invention relates to apparatus for use with internal combustion engines and compressors for testing and analyzing the operation of the engine. It is relatively conventional to test the compression or pressure in the cylinders of internal combustion engines or compressors to determine whether or not each cylinder is functioning properly, and, if not, the probable cause of the malfunction. Compression testing of automobile internal combustion engines is relatively simple but the power testing of internal combustion engines under load is substantially more difficult and critical due to the higher temperatures and pressures involved. Some industrial engines and compressors are supplied with a separate port on each cylinder to which a test apparatus may be attached periodically for analyzing the pressure variations in that cylinder during normal operation of the engine. Occasionally, test ports are installed in other engines and compressors after they are operational. Various types of connectors and transducers have been used to attempt to obtain reliable pressure testing through such ports on industrial engines but numerous difficulties and disadvantages exist with respect to all of the prior devices. Some prior devices require the engine to be stopped between the testing of each cylinder for installing and removing the test apparatus. Some devices have used valves connected to the ports in an attempt to avoid the necessity of stopping the engine between cylinder tests but such valves generally have been unsatisfactory due to sticking or leaking because of the extreme temperatures and pressures and because of carbon buildup in the long clearance pocket created. Still other devices have been very difficult to install and remove due to the design of the engine and the heat generated. Many of the prior devices become overheated during use and cause improper glow plug detonation during operation thereby adversely influencing the test results and the engine operation.
Another problem that has been encountered with prior engine testing equipment is that the pressure transducers installed on the engine which develop the pressure signal transmitted to the visual or printed readout equipment are subjected to such high temperatures that the expensive transducers have exhibited a rather short useful life. Some transducers have been constructed with means for supplying compressed air through the transducer to reduce the overheating but such arrangement has not eliminated the problem. Moreover, the numerous different types of engines with their different types of test ports as well as the numerous different types of transducers have heretofore precluded any standardized or uniform solution to the various problems of engine analyzers.
It is an object of this invention to provide a novel form of engine analyzer apparatus which employs a valve means installed on each cylinder and an adapter for connecting between the valve means and the transducer with means for supplying a cooling fluid to the adapter to eliminate overheating of the transducer and glow plug detonation during testing. It is a further object of this invention to provide means for injecting water in the compressed air supplied as the cooling fluid to the adapter for supplementing the cooling under extreme conditions. A still further object of this invention is to provide the apparatus with a valve means which is easily and automatically opened by installation of the adapter and automatically and reliably closes upon removal of the adapter without any additional manipulation. Still another object of this invention is to provide an unloading device that is operable with the valve for unloading an engine cylinder.